If a binomial distribution has mean 2.4 and variance is 1.44, then n = 
 

Given  $\mathrm{np}=2.4 -\left(1\right)$

and   $\mathrm{npq}=1.44 -\left(2\right)$ 

 $$\begin{gathered} Now \frac{\left(2\right)}{\left(1\right)} \\ \Rightarrow \frac{\mathrm{npq}}{\mathrm{np}}=\frac{1.44}{2.4} \\ \Rightarrow \mathrm{q}=\frac{3}{5} \end{gathered}$$

Now $\mathrm{p}=1-\mathrm{q}=\frac{2}{5}$

from (1) $\mathrm{n}\left(\frac{2}{5}\right)=2.4 \Rightarrow \mathrm{n}=\frac{24}{10}\times \frac{5}{2}=6$